Engineered nanomaterials: toward effective safety management in research laboratories

Safety Assessment of Nanomaterials in Cosmetics: Focus on Dermal and Hair Dyes Products

Nanomaterials use in cosmetics is markedly enhancing, so their exposure and toxicity are important parameters to consider for their risk assessment. This review article provides an overview of the active cosmetic ingredients used for cosmetic application, including dermal cosmetics and also hair dye cosmetics, as well as their safety assessment, enriched with a compilation of the safety assessment tests available to evaluate the different types of toxicity. In fact, despite the increase in research and the number of papers published in the field of nanotechnology, the related safety assessment is still insufficient. To elucidate the possible effects that nanosized particles can have on living systems, more studies reproducing similar conditions to what happens in vivo should be conducted, particularly considering the complex interactions of the biological systems and active cosmetic ingredients to achieve newer, safer, and more efficient nanomaterials. Toward this end, ecological issues and the toxicological pattern should also be a study target.

Sonosensitive capsules for brain thrombolysis increase ischemic damage in a stroke model

Background

Ischemic stroke is the most common cerebrovascular disease and is caused by interruption of blood supply to the brain. To date, recombinant tissue plasminogen activator (rtPA) has been the main pharmacological treatment in the acute phase. However, this treatment has some drawbacks, such as a short half-life, low reperfusion rate, risk of hemorrhagic transformations, and neurotoxic effects. To overcome the limitations of rtPA and improve its effectiveness, we recently designed sonosensitive sub-micrometric capsules (SCs) loaded with rtPA with a size of approximately 600 nm, synthesized using the layer-by-layer (LbL) technique, and coated with gelatine for clot targeting. In this study, we evaluated the rtPA release of ultrasound (US)-responsive SCs in healthy mice and the therapeutic effect in a thromboembolic stroke model.

Results

In healthy mice, SCs loaded with rtPA 1 mg/kg responded properly to external US exposure, extending the half-life of the drug in the blood stream more than the group treated with free rtPA solution. The gelatine coating also contributed to stabilizing the encapsulation and maintaining the response to US. When the same particles were administered in the stroke model, these SCs appeared to aggregate in the ischemic brain region, probably generating secondary embolisms and limiting the thrombolytic effect of rtPA. Despite the promising results of these thrombolytic particles, at least under the dose and size conditions used in this study, the administration of these capsules represents a risk factor for stroke.

Conclusions

This is the first study to report the aggregation risk of a drug carrier in neurological pathologies such as stroke. Biocompatibility analysis related to the use of nano-and microparticles should be deeply studied to anticipate the limitations and orientate the design of new nanoparticles for translation to humans.

Graphical Abstract

NanoSafe III: A User Friendly Safety Management System for Nanomaterials in Laboratories and Small Facilities

Research in nanoscience continues to bring forward a steady stream of new nanomaterials and processes that are being developed and marketed. While scientific committees and expert groups deal with the harmonization of terminology and legal challenges, risk assessors in research labs continue to have to deal with the gap between regulations and rapidly developing information. The risk assessment of nanomaterial processes is currently slow and tedious because it is performed on a material-by-material basis. Safety data sheets are rarely available for (new) nanomaterials, and even when they are, they often lack nano-specific information. Exposure estimations or measurements are difficult to perform and require sophisticated and expensive equipment and personal expertise. The use of banding-based risk assessment tools for laboratory environments is an efficient way to evaluate the occupational risks associated with nanomaterials. Herein, we present an updated version of our risk assessment tool for working with nanomaterials based on a three-step control banding approach and the precautionary principle. The first step is to determine the hazard band of the nanomaterial. A decision tree allows the assignment of the material to one of three bands based on known or expected effects on human health. In the second step, the work exposure is evaluated and the processes are classified into three "nano" levels for each specific hazard band. The work exposure is estimated using a laboratory exposure model. The result of this calculation in combination with recommended occupational exposure limits (rOEL) for nanomaterials and an additional safety factor gives the final "nano" level. Finally, we update the technical, organizational, and personal protective measures to allow nanomaterial processes to be established in research environments.

Fractional Exhaled Nitric Oxide and Nanomaterial Exposure in Workplaces

Background:

The widespread application of engineered nanomaterials (ENMs) and the increasing likelihood of general and occupational exposure raised concerns on their possible human health impact. ENMs, in fact, may induce alterations in different organ systems, and particularly in the respiratory tract. This makes it important to identify possible biomarkers of early lung effect in exposed workers. In this regard, the possibility to use the fractional exhaled levels of nitric oxide (FENO) in biological monitoring has attracted considerable interest.

Objective:

To comprehensively assess the role of FENO as a possible biomarker of lung effect in ENM exposed workers.

Methods:

A systematic search was performed on Pubmed, Scopus, and ISI Web of Knowledge databases according to the PRISMA guidelines.

Results:

Seven studies investigated FENO in workers exposed to different kinds of metal-(i.e. silver and gold), metal oxide- (titanium and silica dioxide), and carbon-based ENMs (carbon nanotubes). In general, no significant alterations were detected between exposed workers and controls.

Conclusions:

Definite conclusion on the function of FENO in occupational biological monitoring cannot be extrapolated due to the limited number of available studies and the small size of investigated populations. Additionally, the lack of environmental monitoring data and the fragmented knowledge on ENM modes of action prevent to establish dose-response relationships. Future research appears necessary to deeply define the possibility to employ FENO as an early biomarker of lung effects taking in consideration possible occupational exposure issues, i.e. differently characterized ENMs and work tasks, as well as individual influencing factors, i.e. smoking and atopy.

Health and Safety Concerns Related to CNT and Graphene Products, and Related Composites

The use of Carbon Nanotubes (CNT) and Graphene increased in the last decade and it is likely to keep increasing in the near future. The attractiveness of their properties, particularly the possibility to enhance the composites performance using a tailor made methodology, brings new materials, processes and products for highly demanding industrial applications and to the market. However, there are quite a lot of health/safety issues, as well as lack of understanding and standards to evaluate their effects. This paper starts with a general description of materials, processes and products dealing with CNT and graphene. Then, an overview of concerns related to the health and safety when handling, researching, producing and using products that include these materials is presented. It follows a risk management approach with respect to simulation and evaluation tools, and considering the consensual limits already existing for research, industry and consumers. A general discussion integrating the relevant aspects of health and safety with respect to CNT and graphene is also presented. A proactive view is presented with the intention to contribute with some guidelines on installation, maintenance, evaluation, personal protection equipment (PPE) and personnel training to deal with these carbon-based nanomaterials in research, manufacture, and use with composite materials.

Assessment of occupational exposure to engineered nanomaterials in research laboratories using personal monitors

Exposure assessment is a key stage in the risk assessment/management of engineered nanomaterials. Although different sampling strategies and instruments have been used to define the occupational exposure to nano-scale materials, currently there is no international consensus regarding measurement strategy, metrics and limit values. In fact, the assessment of individual exposure to engineered nanomaterials remains a critical issue despite recent innovative developments in personal monitors and samplers. Hence, we used several of these instruments to evaluate the workers' personal exposure in a large research laboratory where engineered nanomaterials are produced, handled, and characterized in order to provide input data for nanomaterial exposure assessment strategies and future epidemiological studies. The results obtained using personal monitors showed that the workplace concentrations of engineered nanomaterials (lung deposited surface area and particle number concentrations) were quite low in all the different workplaces monitored, with short spikes during the execution of some specific job tasks. The sampling strategy was been adopted on the basis of an Organisation for Economic Cooperation and Development (OECD) suggestion for a tiered approach and was found to be suitable for determining the individual exposure and for identifying possible sources of emission, even those with very low emission rates. The use of these instruments may lead to a significant improvement not only in the exposure assessment stage but, more generally, in the entire risk assessment and management process.

Quantifying environmental and personal risks of nanotechnology for industry

Regulators continue to pursue a comprehensive, generalisable, transparent, reliable, accurate and universally commended injury risk assessment methodology for nanomaterials. After a decade of intensive effort, it emerges that many of the prototype risk metrics are uninformative. This situation has given rise to practical, if non-validated, guidance in the form of control banding recommendations. While informative these are often logically deficient and take no account of risk context as captured in the concept of risk appetite. What emerges from an understanding of risk and from the usable data is the clear need for industry and insurers to agree a risk evaluation scheme based on threshold-for-concern and which motivates industry choices to achieve a below-threshold rating. The generalisable risk metrics for such an approach are listed in this paper.